Infrared imaging devices may include a window or lens in front of a focal plane array that detects incoming thermal image radiation. Construction of these imaging devices often occurs in clean rooms, so-called due to their relative absence of environmental and atmospheric impurities, e.g., dust particulate matter. Such impurities may settle on an optical surface (e.g., a window or lens) that is within the optical focal field.
These environmental factors may cause inconsistencies or flaws in the optical surface (e.g., damage caused by such impurities and/or settling of such impurities on the optical surface) and therefore the resulting image data obtained by the infrared imaging device. This concern is particularly true for an optical surface that is located close to the sensor array such that the inconsistencies or flaws are in relatively good focus. Consequently, if such an optical surface remains open to environmental factors after construction of the infrared imaging device, those environmental factors may degrade the window or lens over time resulting in poorer performance of the device.